imageCLASS MF743Cdw - setting to override paper tray when media is in the Multi-Purpose Tray?

[RAGordonDFW]

I'm attempting to find a way to set my paper tray as the default for everyday printing. However, whenever I load paper or checks into the Multi-Purpose Tray, it overrides that default setting and automatically prints to the Multi-Purpose Tray.

Is that possible??  

Thanks for your help !